[ARM] omap: provide a NULL clock operations structure

... and use it for clocks which are ALWAYS_ENABLED.  These clocks
use a non-NULL enable_reg pointer for other purposes (such as
selecting clock rates.)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
index d3213f5..fa99c0b 100644
--- a/arch/arm/mach-omap2/clock.c
+++ b/arch/arm/mach-omap2/clock.c
@@ -271,7 +271,7 @@
 {
 	u32 regval32;
 
-	if (clk->flags & (ALWAYS_ENABLED | PARENT_CONTROLS_CLOCK))
+	if (clk->flags & PARENT_CONTROLS_CLOCK)
 		return 0;
 
 	if (clk->ops && clk->ops->enable)
@@ -301,7 +301,7 @@
 {
 	u32 regval32;
 
-	if (clk->flags & (ALWAYS_ENABLED | PARENT_CONTROLS_CLOCK))
+	if (clk->flags & PARENT_CONTROLS_CLOCK)
 		return;
 
 	if (clk->ops && clk->ops->disable) {